wigenOut-S30 Posted April 18, 2008 Share Posted April 18, 2008 Well, I recently got a extra exhaust manifold, So I decided while Im waiting on my IC piping to get tigged up, I was going to port the exhaust manifold. I used a Carbide bit and a air die grinder. A buddy of mine came over and helped smooth everything out. This is the first time I have tried anything like this. Changes I am hoping to see, Faster spool, alittle more HP and Tq along with more powerband up higher in the revs. I also ported the exhaust housing of the turbo to match the newly ported exhaust manifold. Here are the pics. Here is the Stock exhaust manifold with the larger opening gasket. Here is the ported manifold Comparo side by side stock vs ported close up.. Turbo exhaust housing. Tell me what yall think... Quote Link to comment Share on other sites More sharing options...
BSD Posted April 18, 2008 Share Posted April 18, 2008 Good stuff wigen... I might bust out the die grinder tonight.. lol. Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted April 18, 2008 Share Posted April 18, 2008 Did you do the other side? You can probably port match it with your head or the gasket itself. Looks good! Mario Quote Link to comment Share on other sites More sharing options...
wigenOut-S30 Posted April 18, 2008 Author Share Posted April 18, 2008 Did you do the other side? You can probably port match it with your head or the gasket itself. Looks good! Mario Yes I used the gasket and port mached it with that. Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted April 18, 2008 Share Posted April 18, 2008 Nice job man. Evan Quote Link to comment Share on other sites More sharing options...
speeder Posted April 19, 2008 Share Posted April 19, 2008 Looks good Gabe... That enlarged passage from the front 4 runners looks like you almost doubled its size. That's GOT to improve flow. Quote Link to comment Share on other sites More sharing options...
MJLamberson Posted April 19, 2008 Share Posted April 19, 2008 sweet! something for me to do while Im waiting for time to put the turbo stuff on, how much of a difference do you think it made? Quote Link to comment Share on other sites More sharing options...
wigenOut-S30 Posted April 19, 2008 Author Share Posted April 19, 2008 sweet! something for me to do while Im waiting for time to put the turbo stuff on, how much of a difference do you think it made? wont be able to tell till I get it on the road.. Quote Link to comment Share on other sites More sharing options...
johnc Posted April 19, 2008 Share Posted April 19, 2008 Go back in there with some sanding rolls and smooth out the cuts. Any kind of sharp edge from your porting work will be a stress riser. Over time, through the hundereds of heat cycles that manifold will go through, a crack will start. Quote Link to comment Share on other sites More sharing options...
naviathan Posted April 19, 2008 Share Posted April 19, 2008 Correct me if I'm wrong, but I thought in a turbo application exhaust velocity was more important that flow between the head and turbo, but after the turbo it was flow that was important? So in essence you've really increased your turbo lag by increasing the size of the exhaust runners. Just my $.02 Quote Link to comment Share on other sites More sharing options...
wigenOut-S30 Posted April 19, 2008 Author Share Posted April 19, 2008 Correct me if I'm wrong, but I thought in a turbo application exhaust velocity was more important that flow between the head and turbo, but after the turbo it was flow that was important? So in essence you've really increased your turbo lag by increasing the size of the exhaust runners. Just my $.02 Well we shall see, but I do know that Ivan picked up a pretty substantial amount of power by doing this. Ivans manifold is now on garretts car which was making 460rwhp on pump gas. Now with his new head should be closer to 5XX or so. I am thinking I will actually get boost alittle sooner and flow more at higher RPMs. Quote Link to comment Share on other sites More sharing options...
naviathan Posted April 19, 2008 Share Posted April 19, 2008 I guess if you're engine is built appropriately it should net gains instead of lag. I was just thinking an engine with a basically stock or slightly modded engine would lose out on a manifold port. Made sense in my head anyway... Quote Link to comment Share on other sites More sharing options...
wigenOut-S30 Posted April 19, 2008 Author Share Posted April 19, 2008 I guess if you're engine is built appropriately it should net gains instead of lag. I was just thinking an engine with a basically stock or slightly modded engine would lose out on a manifold port. Made sense in my head anyway... Garretts was about the same as mine is right now, his is bored over to a 3.0 ltr, Mine is still a 2.8, but I have JE forged pistsons, 8:0.1 compression ratio compared to stock 7:4.1. The head has been rebuilt with a 3 angle valve job and port matched. I am not restricted with a AFM now. The faster you can get air into the motor and out of the motor , the more power you will make. Has any one else lost power from porting the exhaust manifold? from what it looks like stock.. its really not designed that great, 4 cly lead through a tiny little hole to the turbo flange, then the other 2 cly are pretty much open. I am expecting some gains, but I doubt they will be huge.. Every little bit helps though. Quote Link to comment Share on other sites More sharing options...
naviathan Posted April 19, 2008 Share Posted April 19, 2008 Well, it's not so much a loss in power as it's an increase in lag. See with the turbo spool up you want the exhaust gasses moving as fast as possible when they hit the turbine so it spins faster. By widening the path the gasses move through you're increasing the flow rate, but decreasing the velocity. Think of two pipes, one 1" and the other 2". If you put 10lbs of pressurized water into the 1" pipe and it exits into the 2" pip the water flow will slow down and you'll lose some of the pressure. This is the same concept for the turbo. If you you "dump" all that pressure into a wider opening you'll lose pressure and speed. I hope that makes sense... Quote Link to comment Share on other sites More sharing options...
Calgary280ZT Posted April 19, 2008 Share Posted April 19, 2008 Great thread, I'll be porting my exhaust manifold this summer, so very timely. Naviathan, I see your point, especially as it might apply to a basically stock engine. Sorry I don't have the experience or technical know how to comment further. I'm hoping to make 350 rwhp with my mods, so I'm expecting there will be plenty of volume and velocity that the exhaust porting will help. Quote Link to comment Share on other sites More sharing options...
wigenOut-S30 Posted April 19, 2008 Author Share Posted April 19, 2008 Well, it's not so much a loss in power as it's an increase in lag. See with the turbo spool up you want the exhaust gasses moving as fast as possible when they hit the turbine so it spins faster. By widening the path the gasses move through you're increasing the flow rate, but decreasing the velocity. Think of two pipes, one 1" and the other 2". If you put 10lbs of pressurized water into the 1" pipe and it exits into the 2" pip the water flow will slow down and you'll lose some of the pressure. This is the same concept for the turbo. If you you "dump" all that pressure into a wider opening you'll lose pressure and speed. I hope that makes sense... before with my hybrid T3/T4 sleeper turbo.. I was getting 18psi @ 3100rpms.. we shall see. Quote Link to comment Share on other sites More sharing options...
240hoke Posted April 21, 2008 Share Posted April 21, 2008 You may want to smooth out the bumps that are right at the runner inlet. i took a whole loota meat outta mine there. Seems like it would really help flow. Quote Link to comment Share on other sites More sharing options...
wigenOut-S30 Posted April 21, 2008 Author Share Posted April 21, 2008 Yeah I touched on them, but I didnt want to port them too much and go through.. Quote Link to comment Share on other sites More sharing options...
Tony D Posted May 1, 2008 Share Posted May 1, 2008 Think of two pipes, one 1" and the other 2". If you put 10lbs of pressurized water into the 1" pipe and it exits into the 2" pip the water flow will slow down and you'll lose some of the pressure. This is the same concept for the turbo. If you you "dump" all that pressure into a wider opening you'll lose pressure and speed. I hope that makes sense... That's not quite apples and apples there. The water analogy assumes the water flow is optimized at 10psi and you open up the pipe. In the exhaust system the exhaust gasses are restricted quite a bit, and their flow is nowhere NEAR optimized in the current passages. And regardless of all that, the turbo manifold dumps into the turbine housing, the most restrictive part of the whole system. It's exactly opposite of the 1" to 2" analogy. It's more like dumping a 2" pipe to a .375 Jet Nozzle! What he has accomplished is making his US Spec Manifold flow more like the Euro Turbo manifold. If you have ever seen the Euro manifold, the runner towards the front is more than 1 5/8" in diameter (meaning larger than the SFP Tubular Manifold some have!) and the step on the turbo inlet flange is eliminated completely compared to the US 2.8 and JDM 2L specification manifolds. The only difference between the 2l JDM turbo and the 2.8l US Spec unit is the A/R on the turbine is .48 as opposed to .63. THAT will make FAR more difference on the spool characteristics of the engine than the removal of restrictive manifolding. As long as that turbine A/R is that small, the exhaust manifold will not be the primary 'velocity device'. The Euro Turbo cars have .82 A/R, with the derestrictive manifold, and 200HP rated power. I have run both the JDM and US Spec turbine housings on a US manifold, and the spool changed noticeably. But cutting the manifold open only helped on the top end, I noticed nothing on the bottom end. Meaning the spool was the same (boost threshold), but the engines seemed much more willing to rev beyond the original 5500rpms of the stock manifold. Quote Link to comment Share on other sites More sharing options...
steveosupremeo Posted May 4, 2008 Share Posted May 4, 2008 So are you saying the .48 AR housing is ok for a 2.8 turbo motor? I ask because I was looking at one and thinking it might be kinda cool for autoX. Just figured it would eat into my HP. Quote Link to comment Share on other sites More sharing options...
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